Air distribution duct assembly



April 1965 J. w. LEE ETAL 3,177,796

AIR DISTRIBUTION DUCT ASSEMBLY 3 Sheets-Sheet 1 Filed Occ. 22, 1962 lim INVENTORS.

do/v W. LEE l V/LL/AM 14/. WHITE April 13, 1 65 J. w. LEE ETAL 3,177,796

AIR DISTRIBUTION DUCT ASSEMBLY Filed Oct. 22, 1962 3 Sheets-Sheet 2 BY W/u/AM 14 WHITE S A T TO/PNE V5 April 13, 1965 J. w. LEE ETAL AIR DISTRIBUTION DUCT ASSEMBLY Filed Oct. 22, 1962 5 Sheets-Sheet a 4 INVENTORS.

J0/v/4 .L Q Vl/lLL/AM W. WHITE ,47 TO/PNE vs at the time of installation.

United States Patent Ofiice 3,177 ,7 96 AIR DISTRBUTION DUCT ASSEh/IBLY Jon W. Lee, Campbell, and William W. White, San Jose,

This invention relates to an air distribution duct as sembly and more particularly to a combination of what has come to be called a diffuser bar with an air supply duct, the two being particularly designed for mating assembly along their entire lengths for ready assembly to each other for the purpose of uniform distribution of air into an inhabited space.

Many building interiors have dropped or false ceilihgs, which are spaced below the structural ceiling or underside of an upper floor of the building, thereby providing space for the location of power and communication conduits and ducts of various types, including a r ducts for the distribution of conditioned air to the occupied space beneath the dropped ceiling. Ceilings of this type frequently are made from modular size panels or tiles, often designed for acoustical control of the room. Because of the necessity for access to the space .above the ceiling, the panels or tiles often are supported at their edges by inverted T-bars which are suspended in a grid Work at the dropped ceiling level.

A diffuser bar of the type referred to herein is usually designed to function as part of the permanent grid work for the support of the false ceiling as well as for directing conditioned air into the room.

The diffuser bar of the invention functions to pass the air from the associated duct into the interior of the room continuously throughout their lengths and to support edges of various ceiling panels and associated elements such as acoustical ceiling panels, light fixtures or recessed panels and the like. i

The space above a false ceiling in this type of construction is cluttered With many different types of conduits and ducts such as those for electrical service, air conditioning, telephones, heating, etc., and frequently a duct to carry the conditioned air to be distributed from one end of the room to the other must extend between various other service conduits and ducts so that the installation of a duct in that space is often difiicult.

In addition, because the diffuser bar also functions as an element of grid work for supporting the ceiling panels it is desirable that the diffuser bar be erected with and joined to the other grid elements before the associated duct is assembled to it.

Various suggestions in prior art constructions have included the combinations of diffuser bars and preformed cylindrical or tubular ducts as Well as ducts assembled from various flat pieces with the assembly taking place Various drawbacks occur in these types of constructions, the most apparent being (1) the problem of shipping preformed tubular duct work, say, 12 inches in diameter and in lengths of from four to eight feet and (2) the problem of accomplishing the assembly of other shapes of ducts, such as polygons, in the relatively limited space above the ceiling grid Work in which the workmen must perform such task. For example, a triangular duct assembled on the diffuser bar in the space above the grid work requires either a preformed duct with its attendant shipping problems,

or theassernbly of three or more flat pieces tokeach other andto the diffuser bar in the limited working space.

it Labor costs for such assemblyare high. The pieces must have air-tight mating flanges and are costly to manufacture.

Patented Apr. 13, 1965 In addition, a duct of circular cross section is preferable to one of polygonal cross section because of the lesser interference with smooth air flow' along its length.

It is, therefore, the principal object ofthe instant invention to provide an air distribution duct assembly comprising an air diffuser bar and a preformed, jacketed, and insulated duct element, which can be shipped and handled in flat condition and, because of cooperative parts on the diffuser bar and the duct blank, readily can be formed into circular cross section at the time of assembly of the duct to the air diffuser bar and will remain in such circular shape, even if later removed and replaced.

It is another object of the instant invention to provide an air distribution duct assembly comprising a dual function diffuser bar for supporting ceiling elementsand distributing air into the room throughout its length and a duct blank, the diffuser bar and the duct blank having cooperating elements for ready assembly and disassembly, and both being designed to facilitate their fabrication in modular lengths such as, for example, four foot lengths, with means for ready butt joining thereof to provide longer lengths of both the diffuser bar and the duct so as to extend the combination any desired distance across the ceiling of a room.

it is another object of the instant invention to provide an air distribution duct assembly in which the air diffuser and air duct are in continuous communication throughout their lengths, with the assembly being supported in place by the air diffuser bar, and each having maintaining the duct in circular shape While assembled and yet allowing easy disassembly when desired.

It is yet another object of the instant invention to provide an air diffuser bar for a dropped ceiling air distribution system and a flat duct blank having a moisture and air proof jacket and a thermal and acoustical insulation layer, the fiat blank being formable into a circular tube and the .bar and blank having simple cooperative engaging means throughout their lengths of retaining them in mating, 'intercomrnunicating relationship and for retaining the duct blank in circular cross section.

Other and more specific objects and advantages of an air distribution duct assembly embodying the invention will be better understood from the specification which follows and by reference to the drawings, in which:

FIG. 1 is afragmentary viewin perspective of an air distribution duct assembly embodying the invention and illustrating how modular lengths thereof may be assembled with each other and with and aswa part of a ceiling support grid Work;

FIG. 2 is a fragmentary, vertical sectional View taken along the line 2-2 of FIG. 1 and shown on an enlarged scale;

FIG. 3 is a fragmentary, horizontal sectional view taken along the line 33 of FIG. 2 and shown on a still further enlarged scale; t

FlG. 4 is a View in perspectiveof a blank for the formation of an air distribution duct for assembly into a combination embodying the invention; it

FIG. 5 is a vertical sectional view, diagrammatical in nature, andillustrating how a duct blank as shown in FIG. 4 is assembled with an air diffuser baras illus- FIGS. 8, 9 and 10 are fragmentary, detailed views in perspective of alternatively usable diverter members for air distribution from a duct assembly embodying the invention;

FIG. 11 is a detailed, perspective view of an assembly strut for assembling elements forming sides of an air diffuser bar to each other and for assembling such air diffuser bars in end to end abutting relationship; and

FIG. 12 is a greatly enlarged vertical sectional view of 7 an air diffuser bar constituting a part of an assembly embodying the invention and particularly illustrating air flo w control means employedtherein.

An air distribution duct assembly according to the invention is generally indicated by the reference number 10 in FIG. 1 and comprises two major components, viz., an air duct 11 and a diffuser bar 12. In an assembly according to the invention the diffuser bar 12 (see FIG. 12)

and flush with dropped ceilings in modern building interior design. The flanges 14 cooperate with similar flanges 16 (FIG. 3) on inverted T-bars 17 which form the remaining elements of a ceiling grid work supporting the various ceiling elements.

All of the inverted T-bars which perpendicularly abut the air diffuser bar 12 are connected thereto by assembly means such as a retaining clip 18 (FIGS. 2 and 3). The clip 18 has a flat vertical body 19 the upper and lower edges of which fit into ways 21 and 21 (FIG. 12) formed at the upper and lower outer sides of the side members 13. Each clip 18 also has an outwardly directed flap 22 (FIG. 3) which has a tongue 23 adapted to be inserted horizontallythrough a slot24 cut in the vertical member of the inverted T-bar 17 and bent over to retain the T-bar 17 tightly against the edge of the flange 14 of the diffuser bar 12 with the flange 14 and the Tbar flange 16 on the side horizontal level. The clips 18 may be slid lengthwise of the diffuser bar 12 in the ways and 21 to properly space the inverted T- ing grid work and usually air diffuser bars 12 extend along the greater dimension of the space into which conditioned air is to be fed and are spaced laterally from and parallel to each other at distances of from two to four or five ceiling panels apart; Inverted T-bars similar to the T-bars 1'7 extend parallelly to the diffuser bars .12 throughout the area between the diffuser bars 12 to supply the remaining elements of the ceiling grid work. The two side members 13 (FIG. 12) of the diffuser 7 bar 12 are assembled to each other in modular lengths,

for example, four tooth lengths, by assembly struts 25 (see also FIGS. -3 and 11). Each of the struts 25 comprises a pair of side plates 26 and a pair of cross plates 27. In the modification illustrated in the drawings'the struts 25 are depicted as being unitary metal extrusions. Each of the side plates 26 has two vertical, outwardly protruding positioning tongues 28 and two vertical outwardly extending and longer retaining tongues 29. At evenly spaced distances, for example, on one foot spacing, along the length of the diffuser bar 12, each of the side members 13 is perforated with pairs of vertical slots 30, each of a size to receive one pair of positioning tongues 28 and retaining tongues 29. A single slot, indicated by the reference number 30a in FIGS. 1 and 3, is cut through each of the side members 13 near each of their ends and at a distance from such end one-half of the distance between the two slots 30 of a pair.

The side members 13 are assembled to each other by several of the struts 25 which are positioned therebetween with their positioning tongues i 28 and their retaining tongues 29 both extending through the slots 30. 'In making the assembly, the operator bends the retaining tongues 29 over toward each other, as illustrated in FIG. 3, to crimp them around the outer sides of the main walls of the side members 13 for a positive assembly of two side members 13 to form a diffuser bar 12.

In erecting an air distribution duct assembly-embody-,

ing the invention, the modular lengths of the diffuser bar 12 are connected in end-to-end relationship, by the use of the struts 25 as illustrated at the left in FIG. 3. One pair of positioning and retaining tongues 28 and 29 of a single strut 25 is inserted into the slot 3fia in the end of one length of a diffuser bar 12 and the other pair of tongues 28 and 29 is inserted into the slot 313a in the end of another diffuser bar, indicated by the reference number 12a. A lineal assembly of any desired length may be made by connecting bars 12 in multiples of four feet and cross cutting a bar 12 midway between the slots 31? of the correct pair to provide an additional length of l, 2 or 3 feet as needed.

Each of the side members 13 is also grooved near its uppermost end with an inwardly opening slot 31, the two slots 31 being horizontally aligned for the reception of the crossbar of hangers 32 through which hooks or eyes on the lower ends of suspension Wires 33 are hooked or twisted to suspend the diffuser bar 12 from the overhead structural ceiling of the building for supporting the diffuser bar 12.

Each of the side members 13 has an outwardly directed, upwardly flared wing 34 along the outer margin of which extends it turned over lip 35. The lower portion of the wing 34 defines the outer side wall of an upwardly open groove 36 and is spaced from the outer side of the side member 13 and below its uppermost end. The groove 3-6 receives and retains the free end of one of a pair of flanges 37 (FIG. 4) which are formed at the longitudinal margins of a jacket 38 of sheetmetal or the like which is a component of a duct blank 39 from which the duct 11 is formed. The flanges 37 are both turned in the same direction (see FIG. 4) so that when the jacket 33 is formed into a cylindrical shape, the flanges 37 are turned outwardly relative therto. The duct blank 39 consists of its jacket 38, having the flanges 37, and a layer of thermal and/or acoustical insulation generally indicated at 4th. The duct blank 39 is fabricated in flat condition with the flanges 37 turned over. The insulation layer id, for example, may be a layer of glass fiber wool densified to a selected degree and with a suitable binder on the fibers to retain them in the densified condition. A series of laterally spaced, longitudinally extending kerfs 4-1 is cut in the inner surface of the acoustical layer 4ft so that when the duct blank 32 is rolled into a cylindrical shape (FIG. 2) the kerfs 41 will close, thus presenting a relatively smooth cylindrical inner surface on the duct,

11 thus formed.

.The duct 11 is assembled to the diffuser bar 12 in an assembly according to the invention after the diffuser bar 12 has been erected as an element of the ceiling support grid work and in the position determined by the configuration and size of the space to which the conditioned air ;is to be delivered. The workman takes one of the duct blanks 39 and engages one of its flanges 37, for example,

the flange indicated by the reference numbers 37a in' 2 1:.) indicated in solid lines in FIG. 5, and then engages the outermost edge of the other one of the flanges 37, i.e.,

the flange 37b in FIG. 5 with the lip of the wing 34 on the other one of the side members 13. The workman then distorts the duct. blank 39 into the position indicated by broken lines in FIG. 5 and slides the edges of its flange 37b downwardly and into the slot as. The workman then pushes inwardly (right to left, FIG. 5) thrusting or shoving a corner i lof the flange 37b and jacket 33 beneath a shoulder corresponding to the shoulder 43.

In some prior constructions, outwardly turned catch lips at the sides of the duct jacket 33 have been engaged with lips, such as the lips 35 (FIG. 12) to retain the duct in place. In such constructions, because there is no contra-fiexure force, the duct assumes an inverted tear drop shape distorting from circular. In the case of a duct embodying the instant invention, however, when the operator releases the duct blank 39, the resiiiency of the metal jacket 38 urges the free lower ends of the flanges 37a and 37b outwardly against the inner side of the wings 34 and the inner sides of the jacket 38, particularly the flanges 37a and 3711 are urged against the outer sides of theside members 13 at a level above the line of engagement of the free ends of the flanges 3'7 with the wings 34. This engagement resists the tendency of the duct to deform from a circular cross section and maintains it in circular cross section.

After a section of duct 11 has been thus emplaced, the Workman slides the next one of the hangers 32 and its suspension wire 33 against the end of the particular length of duct 11 and assembles a second duct length indicated by the reference number 11a in FIG. 1 in abutting relation to the first duct length. The workman then stretches a narrow resilient joint cover 41: around over the joint between the two duct lengths 11 and 1101 by hooking a lip 4'7 (FIG. 2.) with one of the lips 35 on one of the side members 13, bending the joint cover 46 around the outside of the duct sections 11 and 11a and hooking another lip 43 of the cover as behind the lip 35 on the other one of the side members 13.

At an end of a length of diffuser bar 12 where it is desired to block oif the egress of air, the workman affixes an end closure plate 49 (FIGS. 3 and 7) by four assembly screws 50 which extend through holes in the body of or header which is connected to and delivers the conditioned air to the distribution ducts 11. Air passes from the ducts 11 into and through the difluser bars 12 throughout their lengths and is delivered downwardly through the open space between the lower ends of the side elements 13 into the space to be treated. The direction of delivery of the conditioned air from the open lower end of the diffuser bar 12 is controlled by one or more diverters such as the diverter 51 of FIGS. 8 and. 12, 52 of FIG. 9 and 53 of FIG. 10. Each of the diverters 51, 52 and 53 has an upwardly extending tongue 54, 54a or 54b which is grasped by a plurality of resilient clips 55 (FIG. 6). Each of the resilient clips 55 comprises a pair of spaced jaws 56 and outwardly directed support arms 57. The support arms 57 are slidingly engaged in opposed grooves 58 formed in the inner surfaces of the side members 13.

When it is desired that air shall be distributed to only one side from the open bottom of the diffuser bar 12, a diverter 52 is employed which has a body 61 and a damper wing 62 at one side to cut off the flow of air at one side of its tongue 54a.

When it is desiredthat the pattern of diversion of the air flowing out of the diffuser bar 12 be generally downwardly, a diverter 53 (FIG. 10) having a narrow triangular body 59, is employed. This interferes only slightly with the flow of air out of the open bottom of the diffuser bar 12.

When it is desired that the flow of air out of the dilfuser bar 12 shall be more nearly horizontally, a diverter 51 (FIG. 8) having a wider triangular body 60 is employed. The wider body 66 deflects the air generally horizontally out of the flared opening provided by the diverginglower ends of the side members 13. l

As can best be seen by reference to FIG. 12, the pattern of air diversion also can be varied by changing the vertical position of the diverter S1 or 53 relative to the lower ends of the side members 13 by inserting the diverter tongues or 5412 different distances between the jams 56 of the clips 55.

An important improvement in a diffuser bar 12 constructed according to the teachings of the invention lies in the cooperation between the triangular body 6% of the horizontal diverter 51 and deflecting shoulders 63 at the inner side of the support flanges 14 of the side members 133. One of the problems encountered in the use of air flow control means such as the diffuser bar 12 is the discoloration of the surfaces of the ceiling elements closely adjacent the diffuser bar 12. Even though the air delivered to the air distribution ducts 11 and 11a and through the bar 12 to the interior of the space is filtered priorto its distribution, the air currents pick up dust, soot and smokeand deposit them on the ceiling surfaces.

We have discovered that by placing an abrupt, downwardly directed shoulder, such as the deflecting shoulders as, at the outer sides of the passages between the side members 13 and the diverter body 60, the air is deflected sharply downwardly at the outer sides of thesepassages so that air borne particles are also directed downwardly and are not carried up and into contact with the under surfaces of the ceiling elements. While the precise size of the deflecting shoulders 63 is not critical, they should be so directed as to constitute definite obstructions to the flow of air along the outer margins of the spaces,.thus to produce the abrupt change in direction of flow downwardly away from the level of the ceiling which is necessary to deflect the air borne materials. (Such materials are shown in greatly exaggerated scale, of course, in FIG. 12, as being downwardly deflected, out of the air flow pattern.) 1 r Having described our invention we claim:

1. An air distribution duct assembly comprising a diffuser bar consisting of a pair of generally parallel, vertically extending, spaced side members and means for retaining said side members in fixed relationship to each other for forming an elongated conduit open at top and bottom for the passage of air vertically therethrough, an

- air duct consisting of a resilient sheet material jacket and an insulating layer laminated thereto, cooperating means on the longitudinal edges of said jacket and on the outer sides of said side members near the upper parts thereof for disengageable interlocking when said jacket is cylindrically curved around said layer and said jacket edges placed in embracing relationship with said diffuser bar, said cooperating means comprising an upwardly directed lip spaced laterally from the outer side of each of said side members and defining therewith an upwardly open groove at a level beneath the uppermost end of said side member, an outwardly directed flange portion at each edge of said duct jacket and engageable in one of said grooves,

and a portion of each of said side members located above said groove and engageable with a part of the inner surface of said jacket, when said jacket is cylindrically curved, for preventing inward flexure thereof, relative to said side member.

2. An air distribution duct assembly according to claim 1 in which the flange portion of the duct jacket and the 7 of the duct jacket where the flange thereof joins the main portion thereof for preventing direct vertical separation of said jacket from the diifuser bar.

4. In an air distribution duct assembly having a generally tubular air duct having a resilient sheet material jacket, said jacket defining an axially extending air discharge slot for said duct, the improvement consisting of an air diffuser bar comprising, in combination, a pair of identical side members each having a generally vertical body, means for positioning said side members with their bodies in back-to-back, horizontally spaced relationship, the inner surfaces of said members defining an open air passageway therebetween, each of said members having enga' -eable in said grooves.

5. A duct assembly according to claim 4 in which the flanges are substantially flat and the free ends thereof are directed outwardly relative to the interior of said duct, said free ends of said flanges being adapted to seat in the grooves and to bear against the lower parts of the wings for preventing direct outward disengagement of said flanges therefrom with the flat inner surfaces of said flanges bearing against the upper portions of the side members for preventing inward flexure of the portions of said jacket immediately adjacent said flanges.

6. In an air distribution duct assembly having a diffuser bar and a removable air duct therefor, said bar comprising spaced side members forming a conduit open at top and bottom for the passage of air vertically therethrough and said duct comprising a resilient sheet material jacket having parallel, longitudinal edges, the improvement consisting of cooperating means for removably retaining said duct jacket in cylindrical shape with the longitudinal edges thereof embracing at least the uppermost portion of said diliuser bar, said cooperating means comprising, in combination, a flange portion at each longitudinal edge of said jacket, said portion being turned outwardly relative to the interior of said duct when assembled on said diffuser bar in cylindrical form, and means on the outer sides of said side members forming upwardly open grooves having 'outer side walls that are spaced from the outer sides of said side members and that are below the uppermost ends of said, side members at such distance that when said flanges are inserted into said grooves with said duct jacket in cylindrical shape, the free ends of said flanges bear against said outer side walls of said grooves and the inner sides of said jacket bear against said side members at a level above the line of engagement of said free ends with v said outer side walls.

g are flat and extend radially relative to the interior of the duct when assembled on the diffuser bar with the free ends of said flange-s lying in said grooves and the fiat inner sides of said flanges lying against the outer sides of said side members. i

8. A diffuser bar for an air duct distribution system employing an air supply duct consisting of a flat rectangular jacket of resilient sheet material and a layer of insulating material laminated to one side of said jacket, said jacket having flat, substantially right angular, narrow flanges along its longitudinal edges, said flanges being turned away from said layer of insulating material, said diffuser bar comprising, in combination, (1) a pairof identical, elongated side members, each of said side members having a vertically extending body comprising, (a) an outwardly extending, overlying shoulder near the upper end of said body, (51) a first substantially fiat outer surface portion beneath said shoulder, said surface having a height at least equal to the width of the flanges on said duct jacket, (0) an upwardly and outwardly flaring wing integral with said body and forming at the junction therewith an upwardly open groove extending longitudinally along the bottom edge of said first flat outer surface portion, ((1) an upwardly extending lip on the end of said wing, (e) a second substantially flat outer surface portion beneath the junction of said wing with said body, there being pairs of vertical slots cut through said second flat surface portion at uniformly spaced intervals therealong, (f) an outwardly angled lower portion near the bottom of said body for defining one side of an elongated air discharge opening, g) an outwardly extending horizontal ceiling element support flange on the lower end of said angled portion, (11) and an abrupt, vertical shoulder at the junction of the inner surface of said angled portion and the under side of said support flange, (2) a plurality of cross struts fixed in said pairs of vertical slots in said second flat surface portion, each of said cross struts having spacing means and retaining means, said struts mounting said side members in back-to-back relationship with said overlying shoulder, said wings, said first and second flat surface portions, said angled lower portions and said support flanges on the outer sides of said side members, and (3) a triangular diverter having a flat bottom and upwardly converging side walls mounted in the air discharge opening between said outwardly angled portions of said side members for diverting air flowing therethrough and dividing such opening into two sections, at least one of said sections being open for the passage of air therethrough and along the inner surface of the corresponding one of said outwardly angled portions into deflecting engagement with the corresponding one of said vertical shoulders.

References Cited by the Examiner UNITED STATES PATENTS 2,715 ,867

ROBERT A. OLEARY, Primary Examiner. 

1. AN AIR DISTRIBUTION DUCT ASSEMBLY COMPRISING A DIFFUSER BAR CONSISTING OF A PAIR OF GENERALLY PARALLEL, VERTICALLY EXTENDING, SPACED SIDE MEMBERS AND MEANS FOR RETAINING SAID SIDE MEMBERS IN FIXED RELATIONSHIP TO EACH OTHER FOR FORMING AN ELONGATED CONDUIT OPEN AT TOP AND BOTTOM FOR THE PASSAGE OF AIR VERTICALLY THERETHROUGH, AN AIR DUCT CONSISTING OF A RESILIENT SHEET MATERIAL JACKET AND AN INSULATING LAYER LAMINATED THERETO, COOPERATING MEANS ON THE LONGITUDINAL EDGES OF SAID JACKET AND ON THE OUTER SIDES OF SAID SIDE MEMBERS NEAR THE UPPER PARTS THEREOF FOR DISENGAGEABLE INTERLOCKING WHEN SAID JACKET IS CYLINDRICALLY CURVED AROUND SAID LAYER AND SAID JACKET EDGES PLACED IN EMBRACING RELATIONSHIP WITH SAID DIFFUSER BAR, SAID COOPERATING MEANS COMPRISING AN UPWARDLY DIRECTED LIP SPACED LATERALLY FROM THE OUTER SIDE OF EACH OF SAID SIDE MEMBERS AND DEFINING THEREWITH AN UPWARDLY OPEN GROOVE AT A LEVEL BENEATH THE UPPERMOST END OF SAID SIDE MEMBER, AN OUTWARDLY DIRECTED FLANGE PORTION AT EACH EDGE OF SAID DUCT JACKET AND ENGAGEABLE IN ONE OF SAID GROOVES, AND A PORTION OF EACH OF SAID SIDE MEMBERS LOCATED ABOVE SAID GROOVE AND ENGAGEABLE WITH A PART OF THE INNER SURFACE OF SAID JACKET, WHEN SAID JACKET IS CYLINDRICALLY CURVED, FOR PREVENTING INWARD FLEXURE THEREOF, RELATIVE TO SAID SIDE MEMBER. 